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LT6553 650MHz Gain of 2 Triple Video Amplifier
FEATURES
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DESCRIPTIO
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650MHz -3dB Small Signal Bandwidth 400MHz -3dB 2VP-P Large Signal Bandwidth 150MHz 0.1dB Bandwidth High Slew Rate: 2500V/s Fixed Gain of 2 Requires No External Resistors 75dB Channel Separation at 10MHz 50dB Channel Separation at 100MHz -82dBc 2nd Harmonic Distortion at 10MHz, 2VP-P -72dBc 3rd Harmonic Distortion at 10MHz, 2VP-P Low Supply Current: 8mA per Amplifier 6ns 0.1% Settling Time for 2V Step TTL Compatible Enable ISS 100A when Disabled Differential Gain of 0.022%, Differential Phase of 0.006 Wide Supply Range: 2.25V (4.5V) to 6V (12V) Available in 16-Lead SSOP Package
The LT(R)6553 is a high-speed triple video amplifier with an internally fixed gain of 2. The individual amplifiers are optimized for performance with a double terminated 75 video load and feature a 2VP-P full signal bandwidth of 400MHz, making them ideal for driving very high-resolution video signals. Separate power supply pins for each amplifier boost channel separation to 75dB, allowing the LT6553 to excel in many high-speed applications. While the performance of the LT6553 is optimized for dual supply operation, it can also be used on a single supply as small as 4.5V. Using dual 5V supplies, each amplifier draws only 8mA. When disabled, the amplifiers draw less than 100A and the output pins become high impedance. Furthermore, the amplifiers are capable of turning on in less than 50ns, making them ideal for multiplexing and portable applications. The LT6553 is manufactured on Linear Technology's proprietary low voltage complementary bipolar process and is available in the 16-lead SSOP package that fits in the same PCB area as an SO-8 package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
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RGB Amplifiers Coaxial Cable Drivers LCD Projectors
TYPICAL APPLICATIO
1 2 3 LT6553
Triple Video Line Driver
16 15
5V
Large Signal Transient Response
1.5
RIN 75
+ - 370 370
14
75 75 -5V 75 75 5V 75 75
OUTPUT (V)
VIN = 1VP-P VS = 5V 1.0 RL = 15O TA = 25C 0.5 0 -0.5
4 370 GIN 75 5 6 370 370 - + 370
13
12 11
-1.0 -1.5
- BIN 75 -5V 7 8 +
10
0
2
9
-5V
6553 TA01a
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4 6 8 10 12 14 16 18 20 TIME (ns)
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LT6553
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW EN DGND INR AGND ING AGND INB V- 1 2 3 4 5 6 7 8
G = +2 G = +2 G = +2
Total Supply Voltage (V+ to V-) ............................ 13.2V Input Current (Note 2) ........................................ 10mA Output Current (Continuous) ............................. 70mA EN to DGND Voltage (Note 2) ................................. 5.5V Output Short-Circuit Duration (Note 3) ............ Indefinite Operating Temperature Range (Note 4) ... -40C to 85C Specified Temperature Range (Note 5) .... -40C to 85C Storage Temperature Range .................. -65C to 150C Junction Temperature ........................................... 150C Lead Temperature (Soldering, 10 sec).................. 300C
16 V + 15 V + 14 OUTR 13 V - 12 OUTG 11 V + 10 OUTB 9 V-
ORDER PART NUMBER LT6553CGN LT6553IGN GN PART MARKING 6553 6553I
GN PACKAGE 16-LEAD PLASTIC SSOP TJMAX = 150C, JA = 135C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The q denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VS = 5V, RL = 150, CL = 1.5pF, VEN = 0.4V, VAGND, VDGND = 0V.
SYMBOL VOS IIN RIN CIN PSRR IPSRR AV ERR AV MATCH VOUT IS PARAMETER Input Referred Offset Voltage Input Current Input Resistance Input Capacitance Power Supply Rejection Ratio Input Current Power Supply Rejection Gain Error Gain Matching Maximum Output Voltage Swing
q
ELECTRICAL CHARACTERISTICS
CONDITIONS VIN = 0V, VOS = VOUT/2
q q
MIN
TYP 3 -17
MAX 10 20 50
UNITS mV mV A k pF dB
VIN = 1V f = 100kHz VS (Total) = 4.5V to 12V (Note 6) VS (Total) = 4.5V to 12V (Note 6) VOUT = 2V Any One Channel to Another
q
150 56
400 1 62 1 -1.2 1 4 5
q q q
A/V % % V V
3.25 3.1
3.5 8 11 14 100 100 50
Supply Current, Per Amplifier
q
Supply Current, Disabled, Total IEN ISC SR -3dB BW 0.1dB BW Enable Pin Current Output Short-Circuit Current Slew Rate Small Signal -3dB Bandwidth Gain Flatness 0.1dB Bandwidth
VEN = 4V VEN = Open VEN = 0.4V VEN = V+ RL = 0, VIN = 1V 1V on 2V Output Step (Note 9) VOUT = 200mVP-P VOUT = 200mVP-P
q q q q q
22 0.5 -200 50 1700 -95 0.5 105 2500 650 150
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mA mA A A A A mA V/s MHz MHz
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LT6553
The q denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VS = 5V, RL = 150, CL = 1.5pF, VEN = 0.4V, VAGND, VDGND = 0V.
SYMBOL FPBW FPBW PARAMETER Full Power Bandwidth 2V Full Power Bandwidth 4V All-Hostile Crosstalk tS tR, tF dG dP HD2 HD3 Settling Time Small-Signal Rise and Fall Time Differential Gain Differential Phase 2nd Harmonic Distortion 3rd Harmonic Distortion CONDITIONS VOUT = 2VP-P (Note 7) VOUT = 4VP-P (Note 7) f = 10MHz, VOUT = 2VP-P f = 100MHz, VOUT = 2VP-P 0.1% of VFINAL, VSTEP = 2V 10% to 90%, VOUT = 200mVP-P (Note 8) (Note 8) f = 10MHz, VOUT = 2VP-P f = 10MHz, VOUT = 2VP-P MIN 270 TYP 400 200 -75 -50 6 550 0.022 0.006 -82 -72 MAX UNITS MHz MHz dB dB ns ps % Deg dBc dBc
ELECTRICAL CHARACTERISTICS
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: This parameter is guaranteed to meet specified performance through design and characterization. It is not production tested. Note 3: As long as output current and junction temperature are kept below the Absolute Maximum Ratings, no damage to the part will occur. Depending on the supply voltage, a heat sink may be required. Note 4: The LT6553C is guaranteed functional over the operating temperature range of -40C to 85C. Note 5: The LT6553C is guaranteed to meet specified performance from 0C to 70C. The LT6553C is designed, characterized and expected to meet specified performance from -40C and 85C but is not tested or QA sampled at these temperatures. The LT6553I is guaranteed to meet specified performance from -40C to 85C.
Note 6: The two supply voltage settings for power supply rejection are shifted from the typical VS points for ease of testing. The first measurement is taken at V+ = 3V, V- = -1.5V to provide the required 3V headroom for the enable circuitry to function with EN, DGND, AGND and all inputs connected to 0V. The second measurement is taken at V+ = 8V, V- = -4V. Note 7: Full power bandwidth is calculated from the slew rate: FPBW = SR/( * VP-P) Note 8: Differential gain and phase are measured using a Tektronix TSG120YC/NTSC signal generator and a Tektronix 1780R video measurement set. The resolution of this equipment is better than 0.05% and 0.05. Nine identical amplifier stages were cascaded giving an effective resolution of better than 0.0056% and 0.0056%. Note 9: Slew rate is 100% production tested on the G channel. Slew rate of the R and B channels is guaranteed through design and characterization.
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LT6553 TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current per Amplifier vs Temperature
12 10 VS = 5V RL = VIN = 0V 12
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
VEN = 0V 8 6 4 2 0 -55 -35 -15 VEN = 0.4V
5 25 45 65 85 105 125 TEMPERATURE (C)
6553 G01
Input Referred Offset Voltage vs Temperature
10.0 7.5 VS = 5V VIN = 0V 20
INPUT BIAS CURRENT (A)
OFFSET VOLTAGE (mV)
EN PIN CURRENT (A)
5.0 2.5 0 -2.5 -5.0 -7.5
-10.0 -55 -35 -15
5 25 45 65 85 105 125 TEMPERATURE (C)
6553 G04
Output Voltage vs Input Voltage
5 4 3 VS = 5V RL = 150 5 TA = 125C 4
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
2 1 0 -1 -2 TA = -55C -3 -4 -5 -2.5
TA = 25C
3
TA = -55C TA = 25C
OUTPUT VOLTAGE (V)
-1.5
0.5 1.5 -0.5 INPUT VOLTAGE (V)
4
UW
6553 G07
Supply Current per Amplifier vs Supply Voltage
V- = -V+ VEN, VDGND, VIN = 0V 10 TA = 25C 8 6 4 2 0 12 10 8 6 4 2 0
Supply Current per Amplifier vs EN Pin Voltage
TA = -55C TA = 25C TA = 125C VS = 5V VDGND = 0V VIN = 0V
0
1
2
3 4 5 6 7 8 9 10 11 12 TOTAL SUPPLY VOLTAGE (V)
6553 G02
0
0.5
1.0 1.5 2.0 2.5 3.0 EN PIN VOLTAGE (V)
3.5
4.0
6553 G03
Input Bias Current vs Input Voltage
VS = 5V 0 -20 0 TA = 125C -20 -40 -60 -80
EN Pin Current vs EN Pin Voltage
VS = 5V VDGND = 0V
TA = 125C TA = -55C TA = 25C
TA = 25C TA = -55C
-40
-100 -120
-60 -2.5
-1.5
0.5 1.5 -0.5 INPUT VOLTAGE (V)
2.5
6553 G05
-140 0 1 3 2 EN PIN VOLTAGE (V) 4 5
6553 G06
Output Voltage Swing vs ILOAD (Output High)
VS = 5V VIN = 2V 0
Output Voltage Swing vs ILOAD (Output Low)
VS = 5V VIN = -2V TA = 25C -2 TA = 125C -3 TA = -55C
-1
2 TA = 125C 1
-4
0 2.5 0 10 20 30 40 50 60 70 80 90 100 SOURCE CURRENT (mA)
6553 G08
-5
0
10 20 30 40 50 60 70 80 90 100 SINK CURRENT (mA)
6553 G09
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LT6553 TYPICAL PERFOR A CE CHARACTERISTICS
Input Noise Spectral Density
1000 INPUT NOISE (nV/Hz OR pA/Hz) VS = 5V TA = 25C INPUT IMPEDANCE (k) 1000
REJECTION RATIO (dB)
100 en in
10
1 0.001 0.01 0.1 1 FREQUENCY (kHz) 10 100
6553 G10
Frequency Response vs Output Amplitude
9 8 7 AMPLITUDE (dB) 6 5 4 3 2 1 0 0.1 1 100 10 FREQUENCY (MHz) 1000
6553 G13
VS = 5V RL = 150 TA = 25C
VOUT = 2VP-P AMPLITUDE (dB)
0.1 0 - 0.1 - 0.2 - 0.3 - 0.4 - 0.5 0.1 1 R-CHANNEL
B-CHANNEL
VOUT = 4VP-P
AMPLITUDE (dB)
VOUT = 200mVP-P
Frequency Response with Capacitive Loads
18 16 14 12 AMPLITUDE (dB) 10 8 6 4 2 0 -2 -4 -6 0.1 1 10 100 FREQUENCY (MHz) 1000
6553 G16
OUTPUT IMPEDANCE ()
VS = 5V VOUT = 2VP-P RL = 150 TA = 25C CL = 4.7pF
DISTORTION (dBc)
CL = 0pF
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CL = 10pF
Input Impedance vs Frequency
VS = 5V VIN = 0V TA = 25C 70 60 50 40 30 20 10 0.1 0.01
PSRR vs Frequency
PSRR VS = 5V TA = 25C
100
-PSRR
10
+PSRR
1
0.1
1 10 FREQUENCY (MHz)
100
1000
6553 G11
0 0.001
0.01
0.1 1 FREQUENCY (MHz)
10
100
6553 G12
Gain Flatness vs Frequency
0.5 0.4 0.3 0.2 VS = 5V VOUT = 200mVP-P RL = 150 TA = 25C TYPICAL PART 0 - 20 - 40 - 60 - 80
Crosstalk vs Frequency
VS = 5V VOUT = 2VP-P RL = 150 TA = 25C ALLHOSTILE WORST ADJACENT
G-CHANNEL
- 100 - 120
100 10 FREQUENCY (MHz)
1000
6553 G14
0.1
1
10 100 FREQUENCY (MHz)
1000
6553 G15
Harmonic Distortion vs Frequency
0 - 10 - 20 - 30 - 40 - 50 - 60 - 70 - 80 - 90 - 100 - 110 - 120 0.01 0.1 1 10 FREQUENCY (MHz) 100
6553 G17
Output Impedance vs Frequency
1000 DISABLED VEN = 4V 100
VS = 5V VOUT = 2VP-P RL = 150 TA = 25C
10
HD3 HD2
1
ENABLED VEN = 0.4V
0.1 0.01
VS = 5V RL = 150 TA = 25C 100 1000
6553 G18
0.1
10 1 FREQUENCY (MHz)
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LT6553 TYPICAL PERFOR A CE CHARACTERISTICS
Small Signal Transient Response
0.15 VIN = 100mVP-P VS = 5V 0.10 RL = 150 TA = 25C 0.05
OUTPUT (V) OUTPUT (V)
0.5 0.4 0.3 0.2 0.1 0
0 -0.05 -0.10 -0.15
OUTPUT (V)
0
2
4
6
8 10 12 14 16 18 20 TIME (ns)
6553 G19
Large Signal Transient Response
1.5 VIN = 1VP-P VS = 5V 1.0 RL = 150 TA = 25C 0.5
OUTPUT (V)
PERCENT OF UNITS (%)
PERCENT OF UNITS (%)
0 -0.5 -1.0
-1.5
0
2
4
6
8 10 12 14 16 18 20 TIME (ns)
6553 G22
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Video Amplitude Transient Response
0.9 VOUT = 700mVP-P 0.8 VS = 5V RL = 150 0.7 T = 25C A 0.6 4 3 2 1 0 -1 -2 -3 0 2 4 6 8 10 12 14 16 18 20 TIME (ns)
6553 G20
Large Signal Transient Response
VOUT = 5VP-P VS = 5V RL = 150 TA = 25C
-0.1
-4
0 2 4 6 8 10 12 14 16 18 20 22 24 26 TIME (ns)
6553 G21
Gain Error Distribution
45 40 35 30 25 20 15 10 5 0 -3.0 -2.5 -2.0 -1.5 -1.0 - 0.5 0 0.5 1.0 1.5 GAIN ERROR-INDIVIDUAL CHANNEL (%)
6553 G23
Gain Error Matching Distribution
35 30 25 20 15 10 5 0 -3.0 VS = 5V VOUT = 2V RL = 150 TA = 25C
VS = 5V VOUT = 2V RL = 150 TA = 25C
-2.0 -1.0 0 1.0 2.0 3.0 GAIN ERROR-BETWEEN CHANNELS (%)
6553 G24
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LT6553
PI FU CTIO S
EN (Pin 1): Enable Control Pin. An internal pull-up resistor of 46k defines the pin's impedance and will turn the part off if the pin is unconnected. When the pin is pulled low, the part is enabled. DGND (Pin 2): Digital Ground Reference for Enable Pin. This pin is normally connected to ground. INR (Pin 3): Red Channel Input. This pin has a nominal impedance of 400k and does not have any internal termination resistor. AGND (Pin 4): Analog Ground for 370 Gain Resistor of Red Channel Amplifier. ING (Pin 5): Green Channel Input. This pin has a nominal impedance of 400k and does not have any internal termination resistor. AGND (Pin 6): Analog Ground Shared for the 370 Gain Resistors of both Green and Blue Channel Amplifiers. Additional resistance at this pin will increase the crosstalk between the green and blue channels. INB (Pin 7): Blue Channel Input. This pin has a nominal impedance of 400k and does not have any internal termination resistor. V - (Pin 8): Negative Supply Voltage. V - pins are not internally connected to each other, and must all be connected externally. Proper supply bypassing is necessary for best performance. See the Applications Information section. V - (Pin 9): Negative Supply Voltage for Blue Channel Output Stage. V - pins are not internally connected to each other, and must all be connected externally. Proper supply bypassing is necessary for best performance. See the Applications Information section. OUTB (Pin 10): Blue Channel Output. It is twice the blue channel input, and performs optimally with a 150 load (a double terminated 75 cable). V + (Pin 11): Positive Supply Voltage for Output Stages of Amplifiers B and G. V+ pins are not internally connected to each other, and must all be connected externally. Proper supply bypassing is necessary for best performance. See the Applications Information section. OUTG (Pin 12): Green Channel Output. It is twice the green channel input, and performs optimally with a 150 load (a double terminated 75 cable). V - (Pin 13): Negative Supply Voltage for Output Stage of Amplifiers G and R. V+ pins are not internally connected to each other, and must all be connected externally. Proper supply bypassing is necessary for best performance. See the Applications Information section. OUTR (Pin 14): Red Channel Output. It is twice the red channel input, and performs optimally with a 150 load (a double terminated 75 cable). V + (Pin 15): Positive Supply Voltage for Output Stage R. V+ pins are not internally connected to each other, and must all be connected externally. Proper supply bypassing is necessary for best performance. See the Applications Information section. V + (Pin 16): Positive Supply Voltage. V+ pins are not internally connected to each other, and must all be connected externally. Proper supply bypassing is necessary for best performance. See the Applications Information section.
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LT6553
APPLICATIO S I FOR ATIO
Power Supplies The LT6553 is optimized for 5V supplies but can be operated on as little as 2.25V or a single 4.5V supply and as much as 6V or a single 12V supply. Internally, each supply is independent to improve channel isolation. Do not leave any supply pins disconnected or the part may not function correctly! Enable/Shutdown The LT6553 has a TTL compatible shutdown mode controlled by the EN pin and referenced to the DGND pin. If the amplifier will be enabled at all times, the EN pin can be connected directly to DGND. If the enable function is desired, either driving the pin above 2V or allowing the internal 46k pull-up resistor to pull the EN pin to the top rail will disable the amplifier. When disabled, the DC output impedance will rise to approximately 700 through the internal feedback and gain resistors. Supply current into the amplifier in the disabled state will be primarily through V+ and approximately equal to (V+ - VEN)/46k. It is important that the two following constraints on the DGND pin and the EN pin are always followed: V+ - VDGND 3V VEN - VDGND 5.5V Split supplies of 3V to 5.5V will satisfy these requirements with DGND connected to 0V. In single supply applications above 5.5V, an additional resistor may be needed from the EN pin to DGND if the pin is ever allowed to float. For example, on a 12V single supply, a 33k resistor would protect the pin from floating too high while still allowing the internal pull-up resistor to disable the part. On dual 2.25V supplies, connecting the EN and DGND pins to V- is the easiest way of ensuring that V+ - VDGND is more than 3V. The DGND pin should not be pulled above the EN pin since doing so will turn on an ESD protection diode. If the EN pin voltage is forced a diode drop below the DGND pin, current should be limited to 10mA or less. The enable/disable times of the LT6553 are fast when driven with a logic input. Turn on (from 50% EN input to
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50% output) typically occurs in less than 50ns. Turn off is slower, but is nonetheless below 300ns. Input Considerations The LT6553 input voltage range is from V- + 1V to V+ - 1V. Therefore, on split supplies the LT6553 input range is always larger than the output swing. On a single positive supply, however, the input range limits the output low swing to 2V (1V multiplied by the internal gain of 2). The inputs can be driven beyond the point at which the output clips so long as input currents are limited to below 10mA. Continuing to drive the input beyond the output limit can result in increased current drive and slightly increased swing, but will also increase supply current and may result in delays in transient response at larger levels of overdrive. Layout and Grounding It is imperative that care is taken in PCB layout in order to utilize the very high speed and very low crosstalk of the LT6553. Separate power and ground planes are highly recommended and trace lengths should be kept as short as possible. If input or output traces must be run over a distance of several centimeters, they should use a controlled impedance with matching series and shunt resistances (nominally 75) to maintain signal fidelity. Series termination resistors should be placed as close to the output pins as possible to minimize output capacitance. See the Typical Performance Characteristics section for a plot of frequency response with various output capacitors--only 10pF of parasitic output capacitance causes 6dB of peaking in the frequency response! Low ESL/ESR bypass capacitors should be placed as close to the positive and negative supply pins as possible. One 4700pF ceramic capacitor is recommended for both V+ and V-. Additional 470pF ceramic capacitors with minimal trace length on each supply pin will further improve AC and transient response as well as channel isolation. For high current drive and large-signal transient applications, additional 1F to 10F tantalums should be added on each supply. The smallest value capacitors should be placed closest to the package.
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LT6553
APPLICATIO S I FOR ATIO
If the AGND pins are not connected directly to a low impedance ground plane, they must be carefully bypassed to maintain minimal impedance over frequency. Pin 6 is a shared connection of the gain resistors of both channel G and channel B, and any resistance external to this node can significantly decrease the isolation between those channels. Although crosstalk will be very dependent on the board layout, a recommended starting point for bypass capacitors would be 470pF as close as possible to each AGND pin with one 4700pF capacitor in parallel. To maintain the LT6553's channel isolation, it is beneficial to shield parallel input and output traces using a ground
TYPICAL APPLICATIO
RGB Buffer Demo Board
The DC714 Demo Board illustrates optimal routing, bypassing and termination using the LT6553 as an RGB video buffer. The schematic is shown in Figure 1. All inputs and outputs are routed to have a characteristic impedance of 75 and 75 input shunt and output series
E1 EN J1 50 BNC 1 EN
JP1 CONTROL 12 ENABLE JP2 DGND 12 3 AGND FLOAT E2 DGND 1 2 3 4 LT6553 EN DGND INR AGND ING AGND INB V- V+ V+ OUTR V- OUTG V+ OUTB 16 15 14 13 12 11 10 R1 75 R2 75 R3 75 3 EXT C1 4700pF C2 470pF C3 4700pF
5432
INR
5 4 3 2 5 4 3 2 5 4 3 2
BNC x 3 1 J5 1 J6 1 J7
Z = 75
Z = 75
ING
Z = 75 R4 75 E3 AGND SINGLE 1 DUAL 23 C5 470pF R5 75 R6 75
INB
AGND J3 BANANA JACK 1 J8 BNC
C6 1000pF
JP3 SUPPLY
CAL
5 4 3 2
Figure 1. DC714 Demo Board Schematic
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plane or power supply traces. Vias between topside and backside metal may be required to maintain a low inductance ground near the part where numerous traces converge. ESD Protection The LT6553 has reverse-biased ESD protection diodes on all pins. If any pins are forced a diode drop above the positive supply or a diode drop below the negative supply, large currents may flow through these diodes. If the current is kept below 10mA, no damage to the devices will occur. terminations are connected as close to the part as possible. For ideal operation, a 75 load termination should be connected at the output. The LT6553's gain of 2 will compensate for the resulting divider between the series and load termination resistors.
V+ V+ C4 J2 10F, 16V BANANA 1210 JACK NOTE 5 BNC x3 1 J9 Z = 75 1 J10 1 J11 V- V- J4 BANANA JACK Z = 75 5 4 3 2 5 4 3 2 5 4 3 2 OUTR 5 6 7 8 OUTG Z = 75 9 V- OUTB C7 470pF C8 4700pF C9 10F, 16V 1210 Z = 75 1 J12 BNC 5 4 3 2 CAL
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LT6553
TYPICAL APPLICATIO S
A fourth signal trace is provided at the bottom of the DC714 demo board with dimensions identical to the combined input and output of the other channels. This trace can be used for calibrating the effects of electrical delay and impedance mismatching and is not necessary in an end-user application. Several jumpers and additional connectors are also included to allow for testing of the enable feature and single supply operation. Single Supply RGB Buffer Demo Board The DC743A Demo Board uses the LT6553 in a single supply application with AC coupled inputs and outputs. It is nearly identical to the DC714 RGB Buffer Demo Board but has the additional components required for AC coupling and setting a DC bias point at the input. A schematic of a single channel is shown in Figure 2. AC performance of the LT6553 in the single supply application as shown is nearly identical to performance with dual supplies. The 6.8k and 2.2k bias resistors at the input set up a nominal DC voltage at the input that keeps a video signal
7V TO 12V
INPUT
1/3 LT6553
80.6
2.2k
AGND * AVX 12066D226MAT ** SANYO 6TPB220ML 75
+
Figure 2. Single Supply Configuration, One Channel Shown
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within the input and output common mode range of the part. On a 9V single supply, the input would sit at 2.2V DC, and the output would sit at 4.4V. Due to the 220F coupling cap at the output, the only additional power dissipation due to the positive output voltage is through the feedback and gain resistors. Since those resistors are approximately 740 in series, the additional quiescent current is only 6mA per channel. RGB Video Selector/Cable Driver A video multiplexer can be implemented using the EN pins of parallel LT6553s as shown in Figure 3. In this application, all outputs are connected together and one LT6553 is switched on while the other is switched off. A fast inverter provides a complementary signal to ensure that only one set of R, G and B channels is buffered at any time. As shown, the outputs are connected before the 75 series termination resistors in order to reduce any DC attenuation that may result from the non-infinite output impedance of the disabled LT6553.
22F*
6.8k IN OUT 75
220F**
6553 F02
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LT6553
SI PLIFIED SCHE ATIC
V+ BIAS TO OTHER AMPLIFIERS AGND 370 46k 1k EN IN V- 150 370 OUT V+ V+
DGND V-
6553 SS
PACKAGE DESCRIPTIO
.254 MIN
.0165 .0015
RECOMMENDED SOLDER PAD LAYOUT 1 .015 .004 x 45 (0.38 0.10) .007 - .0098 (0.178 - 0.249) .016 - .050 (0.406 - 1.270) NOTE: 1. CONTROLLING DIMENSION: INCHES INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) 3. DRAWING NOT TO SCALE *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 0 - 8 TYP .053 - .068 (1.351 - 1.727) 23 4 56 7 8 .004 - .0098 (0.102 - 0.249)
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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GN Package 16-Lead Plastic SSOP (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1641)
.045 .005 .189 - .196* (4.801 - 4.978) 16 15 14 13 12 11 10 9
.009 (0.229) REF
.150 - .165 .229 - .244 (5.817 - 6.198) .150 - .157** (3.810 - 3.988)
.0250 TYP
.008 - .012 (0.203 - 0.305)
.0250 (0.635) BSC
GN16 (SSOP) 0502
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LT6553
TYPICAL APPLICATIO
NC7SZ14
R1
G1
B1 75 75 75
SEL
R0
G0
B0 75 75 75
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PART NUMBER LT1259/LT1260 LT1395/LT1396/LT1397 LT1398/LT1399 LT1675/LT1675-1 LT1809/LT1810 LT6550/LT6551 DESCRIPTION Dual/Triple 130MHz Current Feedback Amplifiers Single/Dual/Quad 400MHz Current Feedback Amplifiers Dual/Triple 300MHz Current Feedback Amplifiers 250MHz, Triple and Single RGB Multiplexer with Current Feedback Amplifiers Single/Dual, 180MHz, Rail-to-Rail Input and Output Amplifiers 3.3V Triple and Quad Video Buffers COMMENTS Shutdown, Operates to 15V 800V/s Slew Rate 0.1dB Gain Flatness to 150MHz, Shutdown 100MHz Pixel Switching, -3dB Bandwidth: 250MHz, 1100V/s Slew Rate 350V/s Slew Rate, Shutdown, Low Distortion -90dBc at 5MHz 110MHz Gain of 2 Buffers in MS Package
12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 q FAX: (408) 434-0507
q
U
3.3V 1 2 3 4 5 6 7 8 x2 x2 x2 LT6553 16 15 14 13 12 11 10 9 75 B 75 G 75 R 1 2 3 4 5 6 7 8 x2 x2 x2 LT6553 16 15 14 13 12 11 10 9 NOTE: POWER SUPPLY BYPASS CAPACITORS NOT SHOWN FOR CLARITY -3.3V
6553 F03
Figure 3. RGB Video Selector/Cable Driver
6553f LT/TP 0304 1K * PRINTED IN USA
www.linear.com
(c) LINEAR TECHNOLOGY CORPORATION 2004

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